Earplugs are used to protect a worker""s hearing in a noisy environment. Such earplugs commonly have a front portion for tightly fitting in a person""s ear canal to block noise, and a rear portion that serves as a handle to pull out the earplug from the ear canal. Probably the most common type of earplug in current use is a body of molded slow recovery foam polymer whose front portion is rolled between the fingers to a small diameter, inserted into the ear canal, and allowed to expand while it lies within the ear canal. Such earplugs and other types, must be inserted to a minimum depth in order to effectively block the ear canal. Many persons are leary of inserting objects in their ears, and tend to insert the earplugs less than the minimum amount required for highest noise blocking. Such workers are often not aware of the fact that the earplug has been insufficiently inserted, because the earplug is often inserted far enough to considerably reduce the noise, although not far enough to avoid hearing damage over a long period of time where very loud noises are encountered. Supervisors are responsible for assuring that the workers"" hearing is protected. However, supervisors often cannot determine whether or not the earplug has been sufficiently inserted to obtain full benefit of the noise blocking capability of the earplug. An earplug which readily indicated to a supervisor that it might not be sufficiently inserted to protect the worker""s hearing, would be of value.
In accordance with one embodiment of the present invention, an earplug is provided which aids a supervisor in determining whether or not the earplug is likely to have been fully installed in a worker""s ear canal so as to obtain substantially optimum hearing protection. The earplug has front and rear portions, with the front portion constructed to fit into a person""s ear canal and block noise, and with the rear portion forming a handle for pulling out the front portion from the ear canal. The earplug has a marking at the rear end of the front portion, to provide a visual indication that the front portion has not been fully inserted. If a supervisor notices the marking, then the supervisor has noticed that the earplug has not been fully installed. In some cases, effective blocking is achieved with slightly less than full installation, and a supervisor can note that the marking projects only a small distance out of the ear canal and realizes that the earplug has been installed to a sufficient depth.
The marking is preferably a result of the front and rear portions of the earplug being formed of material of different colors. This can be achieved by molding the front and rear portions of substantially the same material, but with different coloring agents that create different colors, and bonding the front and rear portions together. Thus, if a supervisor observes a location where a color change occurs, where the location is a sufficient distance out of the ear canal to indicate a problem, the supervisor is informed of the problem. The problem of insufficient insertion can be especially common where there is a taper along the front portion of the earplug.
In accordance with one embodiment of the invention, The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.